Fibularis tertius
Encyclopedia
The peroneus tertius is a muscle
of the human body
located in the lower limb.
The muscle arises from the lower third of the anterior surface of the fibula; from the lower part of the interosseous membrane
; and from an intermuscular septum between it and the peroneus brevis muscle. The septum is sometimes called the intermuscular septum of Otto, after the anatomist who first described it.
The tendon, after passing under the superior extensor retinaculum of foot
and inferior extensor retinaculum of foot in the same canal as the extensor digitorum longus, is inserted into the dorsal surface of the base of the metatarsal
bone of the fifth digit.
It is innervated by the deep fibular nerve
, unlike the other peroneal muscles which are innervated by the superficial fibular nerve
, since the peroneus tertius is a member of the anterior compartment.
Its action is that of weak dorsiflexion
of the ankle joint and to evert
the foot at the ankle joint.
This muscle is seldom found in other primates, a fact that has linked its function to efficient terrestrial bipedalism.
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
of the human body
Human body
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs.By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life...
located in the lower limb.
The muscle arises from the lower third of the anterior surface of the fibula; from the lower part of the interosseous membrane
Interosseous membrane of the leg
The interosseous membrane of the leg extends between the interosseous crests of the tibia and fibula, helps stabilize the Tib-Fib relationship and separates the muscles on the front from those on the back of the leg....
; and from an intermuscular septum between it and the peroneus brevis muscle. The septum is sometimes called the intermuscular septum of Otto, after the anatomist who first described it.
The tendon, after passing under the superior extensor retinaculum of foot
Superior extensor retinaculum of foot
The superior extensor retinaculum of the foot of the ankle is the upper part of the anterior annular ligament....
and inferior extensor retinaculum of foot in the same canal as the extensor digitorum longus, is inserted into the dorsal surface of the base of the metatarsal
Metatarsus
The metatarsus or metatarsal bones are a group of five long bones in the foot located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the medial side : the first, second, third, fourth, and fifth...
bone of the fifth digit.
It is innervated by the deep fibular nerve
Deep fibular nerve
The deep fibular nerve begins at the bifurcation of the common fibular nerve, between the fibula and upper part of the fibularis longus, passes infero-medially, deep to extensor digitorum longus, to the anterior surface of the interosseous membrane, and comes into relation with the anterior...
, unlike the other peroneal muscles which are innervated by the superficial fibular nerve
Superficial fibular nerve
The superficial fibular nerve innervates the fibularis longus and fibularis brevis muscles and the skin over the greater part of the dorsum of the foot .It passes forward between the fibularis muscles and the extensor digitorum longus, pierces the deep...
, since the peroneus tertius is a member of the anterior compartment.
Its action is that of weak dorsiflexion
Dorsiflexion
Dorsiflexion is the movement which decreases the angle between the dorsum of the foot and the leg, so that the toes are brought closer to the shin. The movement moving in opposite directions is called plantarflexion...
of the ankle joint and to evert
Eversion (kinesiology)
Eversion is the movement of the sole of the foot away from the median plane. It occurs at the subtalar joint.Peroneus longus and peroneus brevis evert. Both muscles are innervated by the superficial fibular nerve....
the foot at the ankle joint.
This muscle is seldom found in other primates, a fact that has linked its function to efficient terrestrial bipedalism.